2.5.6.2 Accessors for CLIM Elliptical Objects

The following functions apply to both ellipses and elliptical arcs. In all cases, the name
elliptical-object
means that the argument may be an ellipse or an elliptical arc. These generic functions comprise the ellipse protocol. All classes that are subclasses of either
ellipse
or
elliptical-arc
must implement methods for these functions.

ellipse-center-point* [Generic Function]

Arguments: elliptical-object

Summary: Returns the center point of
elliptical-object
as two values representing the coordinate pair.

ellipse-center-point [Generic Function]

Arguments: elliptical-object

Summary: Returns the center point of
elliptical-object
.

ellipse-center-point
is part of the ellipse Application Programmer Interface, but not part of the ellipse protocol. CLIM will supply default methods for
ellipse- center-point
on the protocol classes
ellipse
and
elliptical-arc
that are implemented by calling
ellipse-center-point*
.

ellipse-radii [Generic Function]

Arguments: elliptical-object

Summary: Returns four values corresponding to the two radius vectors of
elliptical-arc
. These values may be canonicalized in some way, and so may not be the same as the values passed to the constructor function.

ellipse-start-angle [Generic Function]

Arguments: elliptical-object

Summary: Returns the start angle of
elliptical-object
. If
elliptical-object
is a full ellipse or closed path, then
ellipse-start-angle
will return
nil
; otherwise the value will be a number greater than or equal to zero, and less than 2π.

ellipse-end-angle [Generic Function]

Arguments: elliptical-object

Summary: Returns the end angle of
elliptical-object
. If
elliptical-object
is a full ellipse or closed path, then
ellipse-end-angle
will return
nil
; otherwise the value will be a number greater than zero, and less than or equal to 2π.